1. Field of the Invention
The present invention relates to a vehicle hood apparatus which protects an obstacle when a running vehicle collides with the obstacle, by reducing a shock to be given to the obstacle when the obstacle hit by the vehicle strikes on a hood and undergoes a secondary collision with the vehicle.
2. Description of the Related Art
When a running vehicle collides with an obstacle, the obstacle in many cases collides with the bumper of the vehicle and then strikes on the hood of the vehicle and undergoes a secondary collision with the top surface of the hood. At this time, the obstacle receives the shock of the collision from the
A known apparatus which reduces such a shock is, for example, the vehicle hood apparatus disclosed in Japanese Patent Laid-Open Publication No. HEI-11-34925. During collision of a vehicle, the vehicle hood apparatus lifts up the rear end of its hood and forms a predetermined space between the hood and its engine room to allow the hood to be deformed downwardly, thereby absorbing collision energy.
When the vehicle collides with an obstacle, the vehicle hood apparatus detects the collision through a collision detecting sensor provided on a front bumper. On the basis of the detection signal, the vehicle hood apparatus inflates the air bag of an actuator. The rear end of the hood is lifted up by a predetermined amount by the inflation of the air bag. The position of the up-lifted hood is held by a hinge mechanism.
The hinge mechanism includes a vehicle-body-side link (equivalent to a bracket) bolted to the vehicle body. A slide hole which extends toward the front and the rear of the vehicle is formed in the vehicle-body-side link. A slide pin is slidably fitted in the slide hole. One end of an intermediate link is pivotally secured to the slide pin. One end side of a hood-side link is secured to the rear end of the hood. The other end of the intermediate link and the other end of the hood-side link are rotatably connected to each other by a connecting pin.
A connecting member made of wire is interposed between the vehicle body and the connecting pin. One end of the connecting member is secured to the vehicle body, and the other end is secured to the connecting pin. When the rear end of the hood is lifted up, the connecting member is brought to a tense state, whereby the movement of the connecting pin toward the rear of the vehicle is restricted. Accordingly, the rear end of the hood is prevented from approaching a windshield more closely than necessary.
However, although the above-described vehicle hood apparatus is art which merely restricts the movement of the rear end of the hood toward the rear of the vehicle, the vehicle hood apparatus needs a large number of components and a complicated structure and has room for improvement.
Moreover, the wire which constitutes the connecting member is loose when the hood is lowered. The loose wire may collide with the vehicle body owing to the vibrations of the vehicle body during running. In this case, since noise occurs due to the collision of the wire with the vehicle body, it is necessary to carefully make design so that the wire does not become a noise source.
The present invention has been made in view of the above-described points, and aims to provide a vehicle hood apparatus which causes a hood holding mechanism to hold a hood lifted up by a predetermined amount and restricts the movement of the lifted-up hood toward the rear of the vehicle, and which allows the hood holding mechanism and a mechanism which restricts the movement of the hood toward the rear of the vehicle to be easily mounted to the vehicle body by means of a simple construction and enables a reduction in the number of mounting steps.
According to a first aspect of the present invention, there is provided a vehicle hood apparatus which, when a vehicle collides with an obstacle, lifts up by a predetermined amount a rear end portion of a hood provided at a front portion of the vehicle and causes a hood holding mechanism to hold the position of the lifted-up rear end portion and restricts a movement of the lifted-up rear end portion toward the rear of the vehicle. The hood holding mechanism includes a bendable link which bends or stretches according to an up or down movement of the hood, and an auxiliary link which restricts movement of the bendable link toward the rear of the vehicle. The bendable link includes a lower link rotatably secured at one end to a bracket mounted to a body of the vehicle, an upper link rotatably secured at one end to the hood, and a hinge portion which rotatably connects the other end of the lower link and that of the upper link to each other. The auxiliary link mechanism includes two links which are connected between a position offset from and close to the hinge portion and a front portion of the bracket, and the two links are connected to each other so that they bend or stretch according to bending or stretching of the bendable link.
According to an embodiment, a specific construction of the auxiliary link mechanism includes, for example, a lower auxiliary link rotatably secured at one end to the front portion of the or bracket, an upper auxiliary link rotatably secured at one end to a position offset from the hinge portion, and an auxiliary hinge portion which rotatably connects the other end of the lower auxiliary link and that of the upper auxiliary link to each other. The other end of the lower auxiliary link and that of the upper auxiliary link respectively have stoppers which engage with or disengage from each other when both links bend or stretch.
During the normal state in which the hood is lowered, the bendable link is folded. If the vehicle collides with an obstacle, the hood is lifted up by a predetermined amount and the bendable link is stretched to hold the lifted-up state of the hood. The movement of the bendable link toward the rear of the vehicle is restricted by the auxiliary link mechanism, whereby the movement of the hood toward the rear of the vehicle is restricted. Accordingly, the rear end of the hood is prevented from approaching the windshield of the vehicle more closely than necessary.
The bendable link and the auxiliary link mechanism are secured to a bracket mounted to the frame of the vehicle body. Accordingly, the hood holding mechanism provided with a mechanism which restricts the movement of the hood toward the rear of the vehicle can easily be mounted to the vehicle body by means of a simple construction and the number of mounting steps is reduced.
Since the mechanism which restricts the movement of the hood toward the rear of the vehicle is constituted by the auxiliary link mechanism, when the hood lies at the original position where it is not yet lifted, the auxiliary link mechanism is folded similarly to the bendable link. Accordingly, the auxiliary link mechanism is prevented from colliding with the vehicle body owing to the vibrations of the vehicle body during running, whereby the occurrence of noise is prevented.
The hood holding mechanism is made of the bendable link and the auxiliary link mechanism, and the number of links used is large. Accordingly, a shock due to a collision of the vehicle is dispersed among these numerous links, whereby an excessive shock is prevented from acting on part of the links or relevant components.